\begin{tikzpicture}
	\tkzDefPoints{0/0/A, 1.5/0/M, 3/0/B}
	\tkzDrawSegments[xianduan={below=0pt}](A,M  M,B)
	\tkzLabelPoints[above=0.3em](A,M,B)
\end{tikzpicture}

